1. The Avengers is a superhero movie so fun, full of so much pure fanboy-wank joy wrapped up in an accessible, relentlessly entertaining package, that I'm not sure anybody needs to make any more comic-book movies; this one might wrap it up. (One suspects they'll still find a way.) Made by and for—but, crucially, not exclusively for—people who love comic-book superhero archetypes and what they stand for, both on the page and in the canon and in a deeply personal, profoundly felt emotional way, it's a downright giddy romp that hits every mark it needs to hit and even invents a few more. The key to this, the reason it works, is writer-director Joss Whedon, who cuts to the very core of what's appealing about this world, about these personalities. The movie runs long, but it never feels long; it's carefully tended by an affectionate director. This is not a grimy reinvention like The Dark Knight; this is a full-fledged, huge-hearted plunge into the pop-art world of comic-book euphoria. This is how you do this right. This is probably as good as it can be done.

2. What'll be a surprise to most people about The Avengers is how consistently funny it is; there are times it feels like you're watching a snappy episode of Cheers, just with tights and capes. (It's tough to come up with a more novel workplace for a workplace comedy than a lair of world-defending superheroes.) Even without some of the more massive-scale battle sequences—including the final battle with aliens through the streets of New York, in which Grand Central Terminal is eradicated and no one has a second to pay it much mind—the movie would work as a straight comedy. Whedon keeps the mythology of the story (which is your typical world-in-peril-only-these-men-can-save-it sci-fi oater) reverent but never gets bogged down in it; this movie charges along at a breakneck, bumrush pace, but light as a feather.

3. There's a legitimate joy involved here, a soaring sense of the possibilities of a movie like this; rather than get weighed down and leadened by the obligation to give so many characters screen time, Whedon finds it liberating, often just throwing a couple superheroes into a scene together just to see what happens. In this way, his episodic television background works for him, basically treating his gaggle of superheroes like rotating cast members, mixing them up in different combinations, all of which work splendidly. He cares about these Avengers as people and as icons, understanding on a fundamental level what makes them interesting, what makes them so enjoyable. Each character gets his own arc, from Tony Stark learning how to overcome his inherent self-interest to Bruce Banner tortured by his duality and lack of control to even Steve Rogers's square-jawed temporal displacement and need to feel in some sort of control, a part of something. Some of these arcs are simple, sure, but it's impressive how well Whedon juggles them all and gives each of them the time and focus they deserve; the heroes here have more story and advancement than they did in their own movies, and there are, like, 10 of them. It was surprising to look back at the movie and realize how well-sketched these traditionally two-dimensional characters really are.

4. Whedon is also helped out by a terrific cast who give better performances in this, honestly, than they did in their own movies. Downey Jr. is more vulnerable and even a little sadder in this than his Iron Man movies; turns out, Tony Stark is more of a joiner than he would have thought. I found Chris Evans stiff and plodding in Captain America, but he's a steady, leveling presence here. Tom Hiddleston has an awfully tough job, playing the main villain to this swarm of superfolk, but he hits every note right; he's menacing without undermining the jovial vibe of the whole enterprise. (He has about 10 different reaction shots in this movie that are dead solid perfect.) But the revelation is Mark Ruffalo, who manages to bring real pathos to The Hulk in a way Eric Bana and Edward Norton (fine actors, both) were never able to approach. When Ruffalo describes his Hulk Events as being "exposed, like a nerve ... it's a nightmare," you feel it; he looks scared, tortured, and dangerous. This makes his ultimate breakthrough—in the film's best scene—all the more moving, and even invests the Hulk's CGI fight scenes (which are cleaner and less artificial-looking than those in the previous Hulk films) with real audience capital. Ruffalo grounds the film in something real, which makes it that much more cathartic when Hulk does, at last, smash.

5. There's a little bit of Marvel movie continuity business that I'm not enough of a comic-book enthusiast to understand; there's a big reveal of some future villain that made the audience gasp, but I had no idea what I was supposed to be gasping about. (It does, however, have my favorite post-credit sequence from any of these superhero movies, a terrific gag that's all the more impressive for how subtly it's set up in the film.) But for all its knowing, heartfelt fanboy fervor, this is a movie for everybody. It is the culmination of several threads and countless storylines, stitched together by someone who knows this world, who feels it as deeply as the most devoted fan but has the skill and wit to convey it in a way that's warm, winning, and a compulsive, almost manic delight. If you're not already a fanboy, it'll turn you into one. It is honestly the most fun I have had at the movies in a long, long time.

Grade: A.

Grierson & Leitch is a regular column about the movies. Follow us on Twitter, @griersonleitch.